An investigator from Nigeria's Department of State Security also confirmed the abduction, but did not disclose when the kidnapping took place.

"We are in touch with the kidnappers. They made some demands and we are trying to see how we can meet it and secure his freedom," the DSS investigator, who wanted to remain anonymous, told the Reuters news agency.

Foreign ministry sources in Freetown told AFP that "this is the first time that a Sierra Leone diplomat has been kidnapped anywhere on posting since independence in 1961".

Frequent abductions

Kidnappings for ransom are a common problem in parts of Nigeria.

This week, two Indian workers were kidnapped on their way to work in central Benue state. The pair have yet to be released.

Last week, three Australians, a New Zealander and a South African were kidnapped along with two Nigerians near the capital of Cross River state in the country's south.